| Year of birth | 1962 |
| Year of call | 1987 |
| Inn | Gray's Inn |
| Circuit | South Eastern |
| Recorder | 2002 |
| QC | 2010 |
| Full CV |
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For many years prior to taking 'Silk' in 2010 Brian O’Neill was recommended in both Chambers and Partners Guide and The Legal 500 as one of the leading juniors at the Criminal Bar.
As a junior he was consistently instructed as the lead advocate both to defend and to prosecute in serious and organised crime (murder, armed robbery, drugs and firearms) and major fraud; being regularly briefed in such cases by leading London solicitors, CPS Special Casework, CPS Homicide Unit and the Fraud Prosecution Service.
He is particularly sought after in 'paper heavy' and substantial multi-handed cases where his exceptional diligence, analytical skills and attention to detail are especially required.
He has also been instructed to represent "celebrity clients" including a number of Premiership footballers.
In addition he undertakes professional discipline and regulatory cases before the General Medical Council, the Solicitors' Disciplinary Tribunal, the Accountancy & Actuarial Discipline Board and the PhonepayPlus Tribunal.
He has represented the Criminal Bar over a number of years as a member of the Bar Council and has previously served as Secretary of the Criminal Bar Association.
Notable Cases
| Case name | Yfeko | Case name | Johnson and others |
| Appearance | Defence | Appearance | Prosecution |
| Detail | Y and a number of others are accused of the murder of another man following a dispute at a house party. The case is listed for trial on 4th October 2010. | Detail | The defendants (of whom there are 29) are members of a gang which carried out more than thirty robberies of jewellers throughout England stealing several millions of pounds worth of watches and other items. The defendants are due to stand their trials in June and November 2010. |
| Case name | D’Mello | Case name | Sacks |
| Appearance | Defence: Leading Junior | Appearance | Prosecution |
| Detail | D and a number of others were accused of the murder of another man following a dispute over D allegedly selling drugs to local children. D was acquitted after an eight week trial. | Detail | S was one of the country’s leading cancer surgeons. It was alleged that he had defrauded private health insurers by submitting hundreds of bills over a number of years claiming for surgical procedures which had not been carried out. |